León Toral was born in Matehuala, San Luis Potosí, into a family of Catholic miners. He moved to Mexico City during the Mexican Revolution and witnessed the then-Constitutionalist general Obregón closing churches and arresting priests who were suspected of collaboration with the dictator Victoriano Huerta. In 1920, he joined the League for the Defense of Religious Freedom, which opposed the governments of Obregón (1920–1924) and Plutarco Elías Calles and reportedly was also involved in the Cristero movement.

During the Calles administration, oppression against the Catholic Church greatly expanded in 1926 under the Calles Law, which provided severe penalties for priests and individuals who violated the provisions of the 1917 Constitution. For instance, wearing clerical garb in public (outside Church buildings) earned a fine of 500 pesos (approximately $250 US at the time); a priest who criticized the government could be imprisoned for five years, with no right to trial by jury.[1]

Some states enacted even more oppressive measures. Chihuahua enacted a law permitting only a single priest to serve the entire Catholic congregation of the state.[2] To help enforce the law, Calles seized church property, expelled all foreign priests, and closed the monasteries, convents and religious schools.[3]

Obregón had been more lenient to Catholics during his time in office, but the Cristeros and almost everyone else believed that Calles was his puppet leader.[4]:399 In 1927, two of León Toral's friends Humberto and Miguel Pro were executed after having been wrongly convicted[citation needed] of plotting to assassinate Obregón. Thus, having been incited by a Catholic nun, Concepción Acevedo de la Llata (also known as Madre Conchita), he decided to assassinate Obregón, whom he blamed for the Mexican government's atrocities against the Catholic Church, if Obregón was reelected.

On 17 July 1928, two weeks after Obregón had been re-elected president, León Toral entered disguised as a caricaturist to La Bombilla, a restaurant in San Ángel, during a banquet organized to honor General Obregón. He made a caricature of Obregón and Aarón Sáenz and showed it to Obregón, who told him the drawing had good likeness and suggested he continue. After Obregón turned around to sit down, León Toral suddenly drew a gun and shot him five or six times in the back, killing Obregón instantly.[4]:403

León Toral was arrested immediately and pleaded guilty, claiming he killed Obregón in order to facilitate the establishment of the Kingdom of Christ.[5] Mother Conchita was also arrested and received a 20-year prison sentence but was pardoned after serving 13 and eventually married Carlos Castro Balda, a bomber of the Mexican Chamber of Deputies.[6][7][8] León Toral was sentenced to death and executed by firing squad in February 1929. His last words were ¡Viva Cristo Rey! (Long Live Christ the King!), the battle cry of the Cristeros.